Design for `xy service install|uninstall|start|stop|status`, backed by the
service-manager crate. Covers the launchd environment problem (PATH snapshot
at install time), the daemon's own rotating log file, and the accepted
blind spot for pre-logger launch failures.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EGntTHCW3sEPy1VBRopNNp
